Post‐release monitoring of site and group fidelity in acoustically tagged stocked fish

Abstract

Understanding post‐release dynamics of stocked fish is essential to successful stock enhancement. This study aimed to match existing life history knowledge to optimise productivity of releases of mulloway, Argyrosomus japonicus (Temminck & Schlegel) into an urban estuary. Passive acoustic telemetry was used to monitor the movement of juvenile mulloway in the Georges River, New South Wales, Australia, and assess the effect of release site and abiotic factors on broad‐scale movements of individuals for 26 weeks. This study found that release site primarily determines the location within the estuary where individuals reside. Water temperature, atmospheric pressure and rainfall did not correlate with fish distribution, although a flood drove fish stocked from upper and mid‐river sites down the estuary in February 2008. Fish gradually returned to these sites over the following 9 weeks. Emigration rates showed an initial downstream migration and an overall egression of ~50% of fish from the release site over 26 weeks. Fish released in this study showed a degree of site‐ and group‐fidelity, with fish distributing according to release site. It is recommended that future releases of mulloway are undertaken directly into nursery habitat in upper estuarine regions to minimise emigration and maximise efficiency of stocking programmes.

Shock, Stress or Signal? Implications of Freshwater Flows for a Top-Level Estuarine Predator

“…Overall, there was a decreasing cline in fish size with increasing distance-to-sea. This is consistent with previous studies which highlight the value of brackish water habitats for mulloway juveniles, which have been deemed important regardless of geographic area [24], [25], [43], [44]. The brackish reaches of temperate estuaries may provide dual benefits for mulloway consistent with the concept of an estuarine nursery (namely abundant food, and lower predation); however, the simple occurrence and use of these areas by juvenile mulloway doesn’t necessarily define it as a “nursery habitat” [45].…”

Use of an acoustic telemetry array for fine scale fish behaviour assessment of captive Paiche, Arapaima gigas, breeders

“…Technical and miniaturization improvements have permitted the development of ultrasonic telemetry equipment in aquatic environments (Crossin et al., ; Hussey et al., ) or GPS system in aerial or terrestrial studies, which allow a much higher positioning frequency (Abecasis, Bentes, Lino, Santos, & Erzini, ; Bellquist, Lowe, & Caselle, ; Binder, Holbrook, Hayden, & Krueger, ; Binder et al., ; Espinoza, Farrugia, Webber, Smith, & Lowe, ; Espinoza, Heupel, Tobin, & Simpfendorfer, ; Farmer, Ault, Smith, & Franklin, ; Lowe, Topping, Cartamil, & Papastamatiou, ; Martins et al., ; Mason & Lowe, ; Pursche, Suthers, & Taylor, ; Semmens, ; Simpfendorfer, Heupel, & Hueter, ; Topping, Lowe, & Caselle, ; Villegas‐Ríos et al., ).…”

FishTracker: a GIS toolbox for kernel density estimation of animal home ranges that accounts for transit times and hard boundaries

“…The incorporation of a weighted least-cost path calculation in the analyses shows additional promise for the analysis of large data sets derived from passive dispersed acoustic arrays (Heupel et al 2006). Analysis of such datasets can rely on interpolation of movements between successive positions detected on different acoustic receivers, which in some cases are dispersed from other receivers (Pursche et al 2013) or represent movements between entirely different arrays.…”